Turning on a gene called Lin28a in old tissue may help cells heal like they are young again.

Lin28a is active in developing embryos and can control how young animals grow and develop. But the gene is not turned on as often in adult cells. When a team of scientists reactivated Lin28a in a group of adult mice with shaved backs, the animals' skin and hair grew back thicker compared with control mice. Mice with the reactivated gene all showed better tissue healing when parts of their ears and paws...